Knowing correct answers (in this case, the identity of the Brights and Braves in the play) is not nearly as important as having some idea about how to go about how to start looking for them.
It is more important for students to experience the delight in the flash of insight that reveals a solution, than to be pressed to "get it". Remember that the goal is for students to appreciate and enjoy the fruits of logical deduction, not to be frustrated by the structures that they must impose on their thinking.
Often, it takes a long time for students to catch on to the tricks that reveal the reasoning processes they need. Students who have trouble should be encouraged, because they will eventually be able to follow and discover the argument. But everyone should recognize that insight arrives on its own timetable, and sometimes the best way to invite it is through a combination of plodding and patience.